Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor having a rotatable hub with one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Each of the rotor blades generally includes a pitch system located in the hub of the wind turbine that is used to safely operate the wind turbine and to extract the maximum amount of power under given wind conditions, i.e. by changing the angle of the rotor blades relative to the wind. Such pitch systems typically include a pitch motor, a pitch gearbox, and a pitch pinion. Further, the pitch motor is typically coupled to the pitch gearbox such that the pitch motor imparts mechanical force to the pitch gearbox. Similarly, the pitch gearbox may be coupled to the pitch pinion for rotation therewith. The pitch pinion may, in turn, be in rotational engagement with a pitch bearing coupled between the hub and one of the rotor blades such that rotation of the pitch pinion causes rotation of the pitch bearing. Thus, rotation of the pitch motor drives the pitch gearbox and the pitch pinion, thereby rotating the pitch bearing and the corresponding rotor blade about a pitch axis.
The mechanical components of wind turbine pitch systems operate under high stress and can fail prematurely over the lifetime of the wind turbine. A failure of the pitch bearing requires the wind turbine to be shut down and repaired. The repair process for the pitch bearing is very complex and can take an extended amount of time to be completed if not scheduled in time. Therefore, the operator of the wind turbine can incur substantial losses due to the downtime of the wind turbine caused by pitch bearing failure.
In view of the aforementioned, there is a need for a pitch bearing monitoring system that can give an early warning signal regarding the bearing condition such that the repair and maintenance process can be improved and the downtime and related losses can be minimized. Thus, the present disclosure is directed to a system and method for monitoring pitch bearing damage using electrical signature analysis that can detect and trend the deterioration in the bearing condition at an early stage.